Production of textile threads



June 10, 1941.-

D. FINLAYSON ETAL 2,244,832

PRODUCTION OF TEXTILE THREADS Filed Nov. 23, .1938

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D'Fl NLAYSON ANT R BEZ swwqs Patented June 10, 1941 PRODUCTION OF TEXTILE THREADS Donald Finlayson and Ronald Bezant, Spondon, near Derby, England, assignors to Celanese Corporation of America, a corporation of Delaware Application November 23, 1938, Serial No. 242,012 In Great Britain December 4, 1937 Claims.

This application relates to the manufacture of textile threads and fabrics, and particularly to the manufacture of textile threads which are crimped along their length, and to the manufacture of mixed threads and fabrics containing such crimped threads.

In U. S. Patents Nos. 2,089,198, 2,089,199 and 2,111,211 processes and apparatus are described whereby a crimp may be imparted to textile threads along their length. In these specifications there are described, inter alia, processes wherein the crimp is imparted to the threads by false twisting the threads and continuously setting the false twist in the threads, e. g. by steaming the threads at a point where they are twisted. It is a characteristic of these false twisting processes that the thread is trapped at the false twisting device so that the false twist is substantially restrained from running past the trapping device. Thus in UJ S. Patent No. 2,111,211 there are described as trapping devices wire hooks, wire loops, slotted discs, floating wire rings and the like.

The degree of crimping produced depends, especially as regards its permanence, on the degree of trapping effected in the false twist device, the higher the angle of contact of the thread with the false-twist device, the more permanent the crimp. Permanence of crimp may also be increased by doubling the crimped yarns with other yarns adapted to take the major part of the tension imparted to the doubled yarn, and so preventing the crimp being pulled out of the crimped component. Thus, in U. S. applications S. Nos. 160,066 and 232,795 filed August 20, 1937. and October 1, 1938, respectively are described various composite yarns and methods of making them in which one or more yarns of crimped artificial filaments are doubled with one or more yarns capable of being shrunk relatively to the crimped yarns, after which the shrinkable yarns are caused to shrink so that subsequently they take the major part of the tension applied to the composite yarns. It has now been found, however, that by doubling two or more yarns, one or more having a more permanent degree of crimp than the rest, a similar effect appears to be produced, in that the more permanently crimped yarn may be employed to prevent the crimp being pulled out of the remaining component or components.

According to the present invention, therefore, a crimped yarn is produced by doubling together one or more crimped components having a higher or more permanent degree of crimp with one or more components having a lower or less permanent degree of crimp. The resultant product is a yarn possessing very valuable wool-like qualities whose crimp has a high degree of permahence by reason of the fact that the more permanently crimped component takes the greater part of the tension to which the yarn is subjected. At the same time, the yarn is crimped throughout, and is therefore of a substantial homogeneous nature. In doubling the different components together it is preferable that the more permanently crimped component should be fed to the doubling operation'at a lower rate than the other component.

A satisfactory yarn for use in the [present invention as the more permanently crimped components may be obtained by the methods described in U. S. Patents Nos. 2,089,198, 2,089,199 and 2,111,211 if the angle of contact of the thread leaving the false twisting device with the trapping device is greater than e. g. up to 360 or more. Thus, especially satisfactory results may be obtained by using a wire hook or wire loop as the trapping device, e. g. as described in U. S. Patent No. 2,111,211 and instead of merely passing the thread under the hook or through the loop, causing the thread to lap round the wire of the hook or loop. The less permanently crimped components for use with the components described above may be obtained by using the devices of any of U. S. Patents Nos. 2,089,198, 2,089,199 and 2,111,211 with an angle of contact at the trapping device less than 90, or they maybe obtained 'by the action of hot aqueou media on cellulose acetate yarn, preferably containing filaments of flat cross-section.

The new process is of especial value in connection with the crimping of threads of cellulose acetate, but it may also be employed in the crimping of threads of other materials. Thus the threads treated may have a basis of an organic derivative of cellulose other than cellulose acetate, e. g. cellulose form-ate, cellulose 'propionate, cellulose butyrate, cellulose acetate-propionate or other organic ester of cellulose, methyl cellulose, ethyl cellulose, butyl cellulose, benzyl cellulose and other ethers of cellulose; The invention may also be applied to the treatment ofthreads of regenerated cellulose, such as viscose or cuprammonium artificial silk, or to the treatment of threads of natural textile materials, e. g. natural silk. Threads consisting of filaments of more than one of the above materials may also be treated.

The invention may be applied to a bundle of a slight contraction -of'the yarn.

smooth continuous filaments, in which case the resulting bundle may be used as a continuous filament yarn containing any desired twist appropriate to the use to which it is to be put, or may be transformed by cutting or otherwise forming into a spun fibre yarn. It the bundle is to be cut into staple fibres it should preferably contain little or no twist after the crimping operation so that the fibres can be easily separated in readiness for the subsequent spinning operation. Again the process may be used to crimp a spun yarn, i. e. a yarn containing fibres cut or otherwise formed into comparatively short.

lengths from continuous filaments. In crimping such a yarn suflicient twist should be retained after setting the crimp to maintain coherence of the yarn. i

The crimped threads produced according to this invention may be converted into fabric form by weaving or knitting.

By way of example a form of apparatus for producing the component yarns to be employed modification of the same detail.

Referring to Fig. l, in the apparatus shown the two yarns are being crimped simultaneously. The two yarns I and 2, which are substantially twistless yarns of straight continuous filaments of cellulose acetate, are drawn from two bobbins 3 and 4 through guides 5 and 6 and are conducted through a further guide 1 to a gate tensioning device 8. The yarns pass together over a roller 9 to a steam chamber. which comprises a main steam pipe l0 adapted to supply a row of crimping devices. For each crimping device there is provided in the pipe ill a nipple it through which the two yarns I and 2 enter and an off-set member I2 provided with a nipple 13 through whichtlie two yarns l arid 2 leave the steam chamber. Wet steam is supplied to the pipe ill.

The yarns leaving the steam chamber are drawn through the middle of a false twisting device It to be described in greater detail hereafter. The false twisting device 14 is mounted I on a bracket l5 carried on a rail l6 secured to 2| and then,'passing upwards, are separated by means of a rod 22 which serves not only to separate the two yarns but also to remove any slight residual twist that might persist along portions-of the yarns. The yarns now in the form of crimped yarns 23, 24 then pass separately over a guide 25 and partly round each of three draw rolls 26, 21-, 28 in turn. The draw rolls 26, 21, 28 are rotated at constant speed and feed the crimped yarns 23, 24 to two bobbins 29, 30 which are driven at a constant peripheral speed lower than that of the rolls 26, 21, 28 to allow The false twisting device It is of the kind described in U. S. Patent No. 2,111,211 and comprises on its upper surface a trapping device 32 shown in greater detail in Figs. 2 and 3. By varying the severity of action of the trapping device 32 yarns having different degrees of crimp result of which a lower degree of crimp is imparted to the yarn.

In Figs. 4 and 5 is shown a modification of the device shown in Figs. 2 and 3 in which an addi tional hook 34 is provided on the upper surface of the false twisting device M. This hook 34 which serves to prevent ballooning of the yarn between the point 35, at which it issues from the top of the false twisting device l4, and the trapping device 32 may, as shown in Fig. 4, be oifset from the straight line between these two points so as to provide a further trapping action.

In using crimped yarns produced by the means described above a very valuable wool-like yarn may be obtained by first doubling together three ends of cellulose acetate yarn of denier which have been crimped by the use of the device in the manner illustrated in Fig. 2, then doubling together three ends of similar yarn which have been crimped by the method illustrated in connection with Fig. 3, then doubling together two ends of the product of the first of these doubling operations with one end of the product of the second'of these doubling operations, the doubling twist being 5 turns per inch reverse, and finally doubling together two of the composite yarns so obtained with 4 turns per inch left-hand doubling twist.

The doubling twist employed will, in general, be quite low, e. g. about 5 turns per inch, in order to preserve as much as possible the voluminosity of the product, and where morethan one doubling operation is employed, as in the example given above, it is desirable that the directions of the various doubling twists should be such that the final product has only a low degree of-twist. Preferably one or more of the yarns is ]fed to the doubling device at a speed greater than that of the other yarn or yarns.

Having described our invention what we desire to secure by Letters Patent is:

1. Process for the production of a crimped yarn which comprises imparting a crimp to at least one component yarn, imparting a higher or more permanent degree of crimp to at least one other component yarn, and doubling together the plurality of components thus crimped, to form a composite crimped yarn.

2. Process for the production of a crimped yarn which comprises imparting a crimp to at least one component yarn, imparting a higher or more permanent degree of crimp to at least one other component yarn, doubling together the plurality of components thus crimped, to form a composite crimped yarn, and in the course of the doubling operation, feeding the component havmg a higher or more permanent degree of crimp at a lower rate than the remaining component.

3. Process for the production of a crimped yarn, which comprises submitting at least two component yarns to a false twisting operation,

trapping each of said components during said false twisting operation so as to restrain the false twist from running past the trapping points, continuously setting the false twist in said components, one of said components being more severely trapped than the other in said false twisting operation so as to produce ahigher'or more permanent degree of crimp therein than in the other and doubling said components together.

4. Process for the production of a crimpedr more permanent degree of crimp therein than in the other, doubling said components together, and during said doubling operation feeding said more severely trapped component at a lower rate than the remaining component.

-5. Process for the production of a yarn, which comprises submitting at least two component yarns containing cellulose acetate to a false twisting operation, trapping each of said components during said false twisting operation so as to restrain the false twist from running past the trapping points, applying to said components, while they contain the false twist, a hot aqueous medium so as to set the false twist in said components, one of said components being more severely trapped than the other in said false twisting operation so as to produce a higher or more permanent degree of crimp therein than in the other and doubling said components together.

, DONALD FINLAYSQK.

RONALD IBEZANT.

crimped 

